Significance and Use
Most waters rarely contain more than trace concentrations of cobalt from natural sources. Although trace amounts of cobalt seem to be essential to the nutrition of some animals, large amounts have pronounced toxic effects on both plant and animal life.
Scope
1.1 These test methods cover the determination of dissolved and total recoverable cobalt in water and wastewater by atomic absorption spectrophotometry. Three test methods are included as follows:
| Concentration Range | Sections | |
| Test Method A—Atomic Absorption, Direct | 0.1 to 10 mg/L | 7 to 16 |
| Test Method B—Atomic Absorption, Chelation-Extraction | 10 to 1000 μg/L | 17 to 26 |
| Test Method C—Atomic Absorption, Graphite Furnace | 5 to 100 μg/L | 27 to 36 |
1.2 Test Method A has been used successfully with reagent water, potable water, river water, and wastewater. Test Method B has been used successfully with reagent water, potable water, river water, sea water and brine. Test Method C was successfully evaluated in reagent water, artificial seawater, river water, tap water, and a synthetic brine. It is the analyst's responsibility to ensure the validity of these test methods for other matrices.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see 11.7.1, 21.10, and 23.10. 7.1 This test method covers the determination of dissolved and total recoverable cobalt in most waters and waste waters. It is the user's responsibility to ensure the validity of this test method in a particular matrix. 7.2 This test method is applicable in the range from 0.1 to 10 mg/L of cobalt. The range may be extended to concentrations greater than 10 mg/L by dilution of the sample. 17.1 This test method covers the determination of dissolved and total recoverable cobalt in most waters and brines. It is the user's responsibility to ensure the validity of this test method in a particular matrix. 17.2 This test method is applicable in the range from 10 to 1000μ g/L of cobalt. The range may be extended to concentrations greater than 1000 μg/L by dilution of the samples. 27.1 This test method covers the determination of dissolved and total recoverable cobalt in most waters and wastewaters. 27.2 This test method is applicable in the range from 5 to 100 μg/L of cobalt. The range can be increased or decreased by varying the volume of sample injected or the instrumental settings. High concentrations may be diluted but preferably should be analyzed by direct aspiration atomic absorption spectrophotometry. 27.3 This test method has been used successfully with reagent water, lake water, river water, well water, filtered tap water, condensate from a medium Btu coal gasification process, and effluent from a wood treatment plant. It is the user's responsibility to ensure the validity of this test method for waters of untested matrices. 27.4 The analyst is encouraged to consult Practice D 3919
